Question Input wanted before I start my 2dof platform

Hi,
New user here, hoping to jump into the world of motion simulation.
I built a stationary cockpit for my son to play flight simulators about 2 years ago, its designed to allow two people to sit next to each other when flying. I now have the idea of adding a 2dof motion platform to the whole rig but wanted a gut check before I start spending too much time on the concept since I havent seen any two seat diy platforms. Obviously the second seat introduces all sorts of balance issues, especially given that im 220lb and he is like 60, not to mention one of us may fly solo occasionally.
Attached is a picture of the flight sim I built as well as a concept for the platform. It would be about 48'x48".
Any initial thoughts or ideas to point me in the right direction would be super helpful, especially when it comes to motors and the best way to mount them. I am a pretty good fabricator and have cnc equipment, etc to produce any parts needed.
Thanks much!

I have no experience with 2DOF rigs but here is a 3DOF 2-seater. The whole rig weights over 300kg fully loaded. So we had to add pneumatic cylinders in the center to counterbalance most of the weight. Otherwise the 3 servo motors would quickly get very hot.

Yes the imbalance when flying solo can be an issue. But if the rig has support in the center (either 2DOF with U-joint or 3DOF with gas springs) at least the weight of the empty rig is supported completely and the actuators are loaded with only half the weight of the pilot. So my estimation is that you probably need 3 times the motor power instead of 2 times with a 2-seat rig compared to single seat.

Another problem with 2DOF is that the rotation point is located externally. This adds a sway component each time you roll and a surge component for pitch. This is not a big problem if the U-joint is directly under the seat. But the furher away it is the more disturbing it gets. With a 2-seater the joint is between the seats and further away from the COG of the pilot. And now, rolling not only generates a sway cue but additionally a heave.

This could be theoretically avoided by replacing the U-joint with some sort of cardanic frame or by building the rig like a roller coaster riding on two curved pair of rails. This way, the center of rotation could be higher, say, between the chests of pilot & co-pilot. But it all gets so complicated I think it's easier to build a 3DOF platform.

Same for the imbalance problem. You could theoretically use a balancer like this and clip it to different points of the rig depending of how many seats are occupied. But it's more expensive than simply using bigger motors that can handle the imbalance.